Field of the Invention
The present invention relates to a substrate processing apparatus that subjects substrates to various types of processing and a substrate processing method using the same.
Substrate processing apparatuses have been conventionally used to subject substrates such as semiconductor wafers, glass substrates for photomasks, liquid crystal displays, and optical disks to various types of processing.
In the substrate processing apparatuses, substrates held by spin chucks, for example, are rotated in horizontal attitudes. Cleaning liquids are supplied to top surfaces or back surfaces of the substrates that rotate, so that the substrates are subjected to cleaning processing. As an example of substrate processing apparatuses that perform such cleaning processing, a rotary substrate processing apparatus disclosed in JP 10-137664 A will be described.
FIG. 14 is a schematic view showing the configuration of the substrate processing apparatus disclosed in JP 10-137664 A. The rotary substrate processing apparatus includes a rotation holder (mechanical spin chuck) 901. The rotation holder 901 has a rotating member 902 in a circular disk shape. The rotating member 902 is horizontally fixed to an upper end of a shaft 904 extending upward from a motor 903 provided below. A plurality of holding pins 906 that hold a substrate W in a horizontal attitude are provided on an upper surface of the rotating member 902.
The shaft 904 extending from the motor 903 is composed of a hollow body, and a back rinse nozzle 907 for cleaning a back surface of the substrate W is inserted into the shaft 904. The back rinse nozzle 907 projects toward the back surface of the substrate W after penetrating a substantially central part of the rotating member 902.
A first discharge port 971 that discharges a cleaning liquid vertically upward is formed at an upper end of the back rinse nozzle 907. A second discharge port 972 that discharges a cleaning liquid sideward is formed on a peripheral wall in the vicinity of the upper end of the back rinse nozzle 907.
When the substrate W is subjected to back surface cleaning processing, an outer edge of the substrate W is held by the plurality of holding pins 906 on the rotating member 902. The motor 903 operates in this state so that the substrate W rotates. The cleaning liquid is supplied to the back surface of the substrate W from the back rinse nozzle 907.
The cleaning liquid discharged from the first discharge port 971 in the back rinse nozzle 907 flows outward along the back surface of the substrate W from the center of the substrate W by a centrifugal force. This causes the whole back surface of the substrate W to be cleaned.
After the substrate W is subjected to the cleaning processing, drying processing may, in some cases, be performed by supplying a gas to the top surface of the substrate W that has been subjected to the cleaning processing. In this case, the top surface of the substrate W is quickly and reliably dried.
In the rotary substrate processing apparatus disclosed in JP 10-137664 A, when a gas is supplied in addition to the cleaning liquid to the back surface of the substrate W, a gas supplying nozzle must be provided within the shaft 904.
When a gas supplying nozzle is newly provided within the shaft 904, the shaft 904 actually increases in diameter while the motor 903 increases in size. As a result, the whole substrate processing apparatus increases in size.
In the rotary substrate processing apparatus disclosed in JP 10-137664 A, when the cleaning liquid is supplied to an area shifted from the rotation center of the substrate W, the cleaning liquid flows outward without passing through the rotation center of the substrate W by a centrifugal force. In this case, the cleaning liquid is not supplied to the rotation center of the substrate W.
In order to supply the cleaning liquid to the whole back surface of the substrate W, therefore, the cleaning liquid must be discharged to the rotation center of the substrate W with high precision. When a plurality of nozzles are provided in the shaft 904, therefore, the processing precision of each of the nozzles and the positional precision of each of the nozzles within the shaft 904 must be sufficiently improved. Since difficulties are involved in work for attaching the plurality of nozzles in the shaft 904 with high precision, however, the manufacturing cost increases.